This invention relates to a sorting conveyor for advancing rectangular flat items such as letters. The items are individually advanced along a guide surface by pusher fingers which are attached to an endless, continuously running finger drive. There is further provided a feeding station or a plurality of serially arranged feeding stations for introducing the articles into the conveying track of the sorting conveyor.
A sorting conveyor of the above-outlined type is disclosed, for example, in German Pat. No. 899,174. The conveying track is formed of an inclined lateral guide surface, a support surface for engaging the lower edge of the flat items and pusher fingers attached to a continuously driven endless chain. The items to be distributed are deposited at the feeding station or feeding stations manually directly on the guide surface. Simultaneously, with the aid of a keyboard, a destination signal is applied to a synchronously switched companion memory. The destination signal causes actuation of the respective diverter in the conveying path, thus effecting a separation (sorting) of the conveyed item at the desired location.
The above-outlined feeding step, however, requires substantial concentration on the part of the operating personnel to avoid incorrect depositions of items, particularly in case the conveying speed is increased. Consequently, such a feeding operation is practically not feasible in case several serially arranged feeding stations are present, because then additional care has to be taken to verify whether or not the next incoming conveying compartment defined between two successive pusher fingers and the corresponding portion of the companion memory has already been occupied at a preceding (upstream) feeding station.
German Pat. No. 929,900 discloses a conveyor for the upright conveying of rectangular flat items. The conveyor includes a feeding station which provides for a mechanical introduction of the items. In accordance with FIGS. 6 and 7 of that patent, the items are deposited from above into a trough-like channel from which, at a desired moment, they are introduced laterally into the conveying track at an acute angle by means of a pair of pinch rollers driven with a speed adapted to the conveying speed. A feeding station constructed in this manner, however, would not be adapted for use in a sorting conveyor to which the invention relates because in case of a conveying track including pusher fingers, the introduction of items may take place only at predetermined moments. Further, all feeding stations operating with a trough-like feed channel for sorting flat items have the disadvantage that subsequent to the deposition of the item, markings thereon, such as an address, are no longer visible.